supererogatory vs superfluous

supererogatory and superfluous both are adjectives.

Word	Noun	Adjective	Verb	Adverb
supererogatory	No	Yes	No	No
superfluous	No	Yes	No	No

As adjectives, supererogatory and superfluous are synonyms defined as:

supererogatory and superfluous: more than is needed, desired, or required

Other synonyms of supererogatory include excess, extra, redundant, spare, supernumerary, surplus.

supererogatory (adjective)	superfluous (adjective)
more than is needed, desired, or required	more than is needed, desired, or required
	serving no useful purpose; having no excuse for being